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Have you noticed there are little white dots on your fish? Are you wondering what that means?

White dots on fish is a sign of white-spot, also known as Ich. Ich is a potentially lethal disease for fish but can have a cure if caught in time. Symptoms include white spots, lethargic fish, and fish scratching themselves on rocks. Ich can be prevented by keeping the water clean in the tank.

It can be overwhelming to think about your fish being sick, but a white spot is easy to treat. So, take a deep breath and keep reading to learn about everything you need to know about white-spot or Ich.

So, What is Ich?

White-spot, or Ichthyophthirius multifilis, is a protozoan fish parasite. This parasite is commonly known as ich because it is a shortened version of the scientific name. All freshwater fish can get ich, but it is most common in aquarium fish.

Ich is very common, but it is very deadly if not taken care of. It spreads quickly, so if one fish has ich, it is likely all of your fish in that aquarium has it as well.

There is a lifecycle for ich that is complicated, but if you know the cycle, it will help with the prevention of ich.

  • The parasite trophant lives in the host fish
    • During this phase, the parasite causes tissue damage and kills the host
  • The mature trophant leaves the fish and attaches to the sides and bottom of the aquarium
  • The reproductive tomont then divides its cells, creating thousands of theronts
  • The infective theronts swim in the water looking for a fish to attack
    • They can live up to three days without a host
  • Then, the cycle repeats

As you can see, the lifecycle is fairly quick, so it is pertinent to check on your fish often.

What is the Cause of Ich?

Stress is a large cause of ich. If your fish is feeling any sort of stress, their immune system is lower, which allows them to catch ich.

Fish can become stressed from many things, such as water temperature, water quality, surroundings, other fish, diet, and many other things. Traveling is also very stressful for fish, so when you get a new fish or have one shipped to your home, that fish will likely be stressed.

It is important to note that fish cannot get ich without the presence of ich in the aquarium. Ich can be presented in an aquarium when any new fish are added to the tank. It also could be dormant in the aquarium already, so it is important to clean the tank before using it.

The healthier the fish is, the less chance there is for the fish to catch ich.


There are many symptoms and identifying factors that go along with ich. If you are paying attention to the behaviors and appearance of your fish, you should be able to identify it quickly. Here is a list of symptoms to look out for:

  • White spots
  • Respiratory distress
  • Severe agitation
  • Loss of appetite
  • Cloudy eyes
  • Frayed fins
  • Abnormal swimming behavior
  • Scratching

White Spots

When a fish has ich, it will have small, white spots on its body and gills. The white spots look like small grains of sand. This is where the nickname “white spot” comes from.

The white spots are cysts that have formed over the parasite itself, which cannot be seen by the naked eye.

Sometimes the white spots are found only on the gills, which makes it hard to identify.

White spots are the most common symptom that comes with ich.

Respiratory Distress

Fish that are in respiratory distress or are having trouble breathing will often swim to the surface and gasp for air.

They also will hang out around the filter output, which has the highest oxygen output in the tank.

You will be able to tell if your fish is in respiratory distress because it looks like they are breathing quickly or struggling to breathe.

Severe Agitation

When a fish is agitated, it usually will swim around sporadically and will not act like itself. This is when knowing your fish’s behavior is important so you have something to compare it to.


Loss of Appetite

This symptom is an easy one to notice. During feeding time, keep an eye on your fish to see if they are eating or not. If this happens a few times, your fish probably does not have an appetite and could be sick.

Cloudy Eyes

Another reason you should frequently check your fish is a cloudy eye. If your fish has ich, it will frequently have cloudy eyes as well.

Cloudy eyes look just as they sound; eyes that are a bit white and cloudy.

Frayed Fins

Frayed fins are also a symptom of fin rot, so be aware of that.

Because ich is a parasite that is causing tissue damage, sometimes the fins will look a bit frayed.

Abnormal Swimming Behavior

Abnormal swimming in fish will look like many things. Sometimes fish swim around quickly for exercise or play, but if your fish is bumping into things and swimming sporadically, this could be a sign of ich.


Going off of abnormal swimming behavior, fish who have ich will purposefully bump into decorations or plants to “scratch” themselves.

The name ich does a good job at depicting what ich feels like to the fish. If you see your fish scratching itself frequently, there is a good chance your fish has ich.

Below is an informative video that explains treatment well.


Luckily, ich is treatable and there are many ways to do so.

  • Chemical treatment
  • Adding salt to the water
  • Raising the tank temperature
  • Water changes

Chemical Treatment

There is a liquid white spot remedy available online or at your local aquatic shop.

Basically, you calculate the volume of the tank and treat it accordingly. This is typically a seven-day dosing period. Your fish will stay in the tank when treated.

You should remove the carbon filter during treatment for it to be effective.

Some people believe that chemicals can be too harsh for your fish, so make sure to do your research and speak to a doctor before adding chemicals to your fish tank.

Adding Salt to the Water

Parasitic diseases do not like salt, so sometimes adding salt to the water will kill off ich.

Typically, you should add 1 tablespoon (Tbps) of salt per 3 gallons of water. You can add it directly to the tank, but some people prefer to dissolve the salt in a cup of water before adding it to the tank.

Raise the Tank Temperature

If your fish can handle it, raising the water temperature is a great way to kill ich.

86 degrees Fahrenheit (30 C) is the goal temperature, but make sure your fish can handle the high temperature before doing so.

Keep the water temperature warmer for 5 days to a week to make sure all of the ich is gone.

Water Changes

Ich lives in the tank, so cleaning out the tank is a good way to get rid of the parasite.

All of the Above

For the best results, adding salt to the water, raising the temperature, and changing the water is the way to treat your fish and tank. The process may have to continue for 5 days to a week to remove the parasite from the fish.

Remember to discontinue the carbon filtration during the treatment.


The best way to prevent ich is to make sure your fish are healthy. A healthy fish has a balanced diet, following its specifications depending on its species.

Also, high water quality in your fish tank will help keep your fish healthy.

When adding new fish to your tank, you should quarantine them for a week to ten days before adding them to the main tank. Before adding new decorations, make sure they are properly cleaned before adding to the tank.

Maintaining a clean tank is another way to prevent your fish from getting ich.

How to Clean Your Fish Tank

Before using your tank, you should clean it thoroughly. One way ich is spread is through the fish tank and decorations. If a fish in your tank gets ich, you will need to clean your entire tank.

Make sure you remove your fish before cleaning the tank.

  1. Unplug the heater and filter
  2. Remove artificial plants and decorations
  3. Clean the inside of the glass
    1. You can use anything from cloth to an algae scraper to clean the glass
  4. Use a gravel siphon to remove 25% of the water
    1. The siphon will remove any dirt or debris that is in the tank
  5. Scrub the decorations and artificial plants
  6. Clean the filter pad, with cold clean water
  7. Replace the filter cartridge
  8. Place the decorations and artificial plants back into the tank
  9. Fill a bucket with tap water, checking the temperature to make sure it matches the tank temperature
  10. Add aquarium salt and water conditioner to the water
  11. Fill the aquarium up slowly
  12. Plug the water heater in
  13. Put your fish back into the tank

Hi, my name is Jordan. I've been in the fishkeeping hobby since my childhood. Welcome to my blog where I help fishkeepers enjoy the hobby by offering free guides, advice, & product reviews. Read more...